Comparing the current Notre Dame defense to that of last season doesn't seem fair to coach Brian Kelly, even if his team returned eight starters on that side of the ball.

Relying on offensive production to help make up for defensive shortcomings might be more difficult Saturday when the 22nd-ranked Fighting Irish host unbeaten Michigan State and the nation's top defense.

Though the Spartans aren't exactly an offensive juggernaut, it hasn't taken much to make Notre Dame look frazzled. Following a 28-6 win over Temple to open the season, the Irish (2-1) allowed their most points in a regular-season game since 2009 in a 41-30 loss to then-No. 17 Michigan on Sept. 7. Last week, they hung on for a 31-24 road win over a Purdue team which had totaled 27 points in its first two games.

Notre Dame is giving up 23.5 points per game after allowing 12.8 in 2012, ranking second in the nation on its way to an appearance in the BCS championship game.

"We're still evolving. It takes time," Kelly said. "Even if you've got guys that are veterans, we have some key positions that have some new players in it. They're coming together."

Michigan State coach Mark Dantonio feels similarly about his offense now that he's settled on Connor Cook as his starting quarterback after plenty of uncertainty.

Cook split time with Andrew Maxwell and Tyler O'Connor through the team's first three games, but the redshirt sophomore went 15 of 22 for 202 yards and four touchdowns in last week's 55-17 win over Youngstown State.

The Spartans (3-0) racked up 547 yards of offense after totaling 562 through their first two games.

"This will be a great experience for (Cook) because he's going to have an environment to play in that's going to simulate really what a lot of Big Ten environments are going to be from this point on," Dantonio said. "That's going to be a period of growth for him."

Michigan State also ran for 277 yards, and Kelly said he doesn't have to remind his team what it has in store Saturday.

"It's not like I have to stand in front of them and get them ready for this fight. They know what kind of fight it's going to be," Kelly said. "This isn't, you know, hey, guys, please listen to me this week. They know what they are going to get from Michigan State."

Tommy Rees has thrown for more than 300 yards and multiple touchdowns in all three of Notre Dame's games. Four of his seven TD passes have gone to DaVaris Daniels, who had eight catches for 167 yards last week.

While the Irish's offense has been solid, it will face a tough test as the Spartans are allowing an average of 177.0 yards, lowest in the nation.

"Very excited about our defense. I know they'll come to play," Dantonio said. "I think they're a confident football team. They like to play, they like playing on a big stage, which is positive."

Kelly said the Irish especially need to be aware of Spartans defensive end Shilique Calhoun, who has scored three touchdowns off turnovers.

"Well, you'd better know where he is. He's tall, he's long, extremely athletic," Kelly said. "You've got to play tough, physical football for four quarters. You've got to take care of the football. All of the little things matter in matchups like this."

Dantonio has been pleased with the leadership role Calhoun has taken on in his second season.

"He has more confidence now. Still a redshirt sophomore," Dantonio said. "He has a lot of charisma. That rubs off on everybody else."

Last season, No. 20 Notre Dame held No. 10 Michigan State to 50 yards rushing in a 20-3 victory Sept. 15 in East Lansing for its second straight win in the series.

The Irish, whose nine-game winning streak in South Bend is their longest since 1997-98, have won two consecutive home meetings with the Spartans after dropping the previous six.